1. Field of Invention
The present invention relates to optical systems and methods, and more particularly to optical systems and methods to photo-stimulate selected portions of the fundus of an eye.
2. Discussion of Related Art
Instruments are available to view and photograph the fundus of a patient's eye. For example, one such instrument in wide use is a fundus camera. FIG. 1 is an example of a conventional fundus camera 100. The fundus camera 100 is one example of an optical system to observe the fundus 102 of a subject's eye 104. The fundus camera 100 has an illumination path 106 and a viewing path 108. A constant illumination may be provided by an incandescence light bulb 110, for example. A brighter flash illumination may be provided by flash bulb 112 for use in conjunction with film-based cameras. Furthermore, the viewing path 108 may be split into a path for direct viewing 114 by a user and a path 116 to a camera 118 for photographing an image of the fundus 102 of the subject's eye 104. The beam splitter 120 may be replaced with a movable mirror 122 in some fundus cameras. The commercial fundus camera 100 is shown as an example and not meant to limit the scope of the current invention.
It is also often desirable to observe or measure subjective or objective responses of the eye or visual system as the fundus undergoes photo-stimulation and more particularly, it is often desirable to observe responses of the eye as selected portions of the fundus undergoes photo-stimulation. Such local photo-stimulation systems that can be used in conjunction with readily available fundus-observation systems such as a fundus camera are not currently available. There is thus a need for improved fundus photo-stimulation devices and methods.